Fixed length encoding is widely used to encode symbols and event outcomes that have equal probability of occurrence. For example, if an event has 240 equally probable outcomes, each of these outcomes are encoded using 8 bits. Similarly, if a communication system is designed to support a maximum of 1000 users, each user is given a 10 bit identification (ID). This constant length ID encoding is efficient when the number of users in the communication system is close to the maximum number of users for which the system is designed. If the number of users at a particular time is much less than the maximum number of users, the fixed length coding is not efficient and suffers from higher than required overhead. This is true for the encoding of identifiers such as connection identifiers (CIDs) in OFDMA based IEEE 802.16 networks.
Thus, a strong need exists for techniques to reduce overhead and increase efficiency in wireless networks such as IEEE 802.16 based networks.
It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements.